Fischell Department of Bioengineering, University of Maryland, College Park, MD 20742, United States of America.
Center for Engineering Complex Tissues, University of Maryland, College Park, MD 20742, United States of America.
Biofabrication. 2022 Feb 23;14(2). doi: 10.1088/1758-5090/ac5220.
Osteoarthritis is a highly prevalent rheumatic musculoskeletal disorder that commonly affects many joints. Repetitive joint overloading perpetuates the damage to the affected cartilage, which undermines the structural integrity of the osteochondral unit. Various tissue engineering strategies have been employed to design multiphasic osteochondral scaffolds that recapitulate layer-specific biomechanical properties, but the inability to fully satisfy mechanical demands within the joint has limited their success. Through computational modeling and extrusion-based bioprinting, we attempted to fabricate a biphasic osteochondral scaffold with improved shear properties and a mechanically strong interface. A 3D stationary solid mechanics model was developed to simulate the effect of lateral shear force on various thermoplastic polymer/hydrogel scaffolds with a patterned interface. Additionally, interfacial shear tests were performed on bioprinted polycaprolactone (PCL)/hydrogel interface scaffolds. The first simulation showed that the PCL/gelatin methacrylate (GelMA) and PCL/polyethylene glycol diacrylate (PEGDA) scaffolds interlocking hydrogel and PCL at interface in a 1:1 ratio possessed the largest average tensile (PCL/GelMA: 80.52 kPa; PCL/PEGDA: 79.75 kPa) and compressive stress (PCL/GelMA: 74.71 kPa; PCL/PEGDA: 73.83 kPa). Although there were significant differences in shear strength between PCL/GelMA and PCL/PEGDA scaffolds, no significant difference was observed among the treatment groups within both scaffold types. Lastly, the hypothetical simulations of potential biphasic 3D printed scaffolds showed that for every order of magnitude decrease in Young's modulus () of the soft bioink, all the scaffolds underwent an exponential increase in average displacement at the cartilage and interface layers. The following work provides valuable insights into the biomechanics of 3D printed osteochondral scaffolds, which will help inform future scaffold designs for enhanced regenerative outcomes.
骨关节炎是一种常见的风湿性肌肉骨骼疾病，通常会影响多个关节。关节反复超负荷会使受影响的软骨持续受损，从而破坏骨软骨单位的结构完整性。已经采用了各种组织工程策略来设计多相骨软骨支架，以再现具有层特异性生物力学特性的支架，但由于无法完全满足关节内的机械需求，这些策略的应用受到了限制。通过计算建模和基于挤出的生物打印，我们试图制造具有改进剪切性能和机械强度界面的双相骨软骨支架。开发了一个 3D 固定力学模型来模拟侧向剪切力对具有图案化界面的各种热塑性聚合物/水凝胶支架的影响。此外，还对生物打印的聚己内酯（PCL）/水凝胶界面支架进行了界面剪切测试。第一次模拟表明，PCL/明胶甲基丙烯酰（GelMA）和 PCL/聚乙二醇二丙烯酸酯（PEGDA）支架以 1:1 的比例互锁水凝胶和 PCL 界面的支架具有最大的平均拉伸强度（PCL/GelMA：80.52 kPa；PCL/PEGDA：79.75 kPa）和压缩应力（PCL/GelMA：74.71 kPa；PCL/PEGDA：73.83 kPa）。尽管 PCL/GelMA 和 PCL/PEGDA 支架的剪切强度存在显著差异，但在两种支架类型的处理组之间未观察到显著差异。最后，潜在双相 3D 打印支架的假设模拟表明，对于软生物墨水杨氏模量（）每降低一个数量级，所有支架在软骨和界面层的平均位移都会呈指数增加。这项工作为 3D 打印骨软骨支架的生物力学提供了有价值的见解，这将有助于为增强再生效果的支架设计提供信息。
